U.S. patent number 8,107,392 [Application Number 12/278,097] was granted by the patent office on 2012-01-31 for method and apparatus for packet aggregation in power line communication network.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Seung-Gi Chang, In-Hwan Kim, Ju-Han Lee, Ho-Jeong You.
United States Patent |
8,107,392 |
Lee , et al. |
January 31, 2012 |
Method and apparatus for packet aggregation in power line
communication network
Abstract
A method and apparatus for packet aggregation in a power line
communication network (PLC) are provided. The method of aggregating
packets includes: by performing a PLC channel estimation,
determining whether or not a channel condition is good; if the
channel condition is good, determining whether or not the data
desired to be transmitted is suitable for packet aggregation
according to the type of data; and if the channel condition is good
and the data desired to be transmitted is suitable for the packet
aggregation, aggregating packets of the data desired to be
transmitted. Since a decision on whether or not to aggregate
packets is determined according to a channel condition at a
physical level and the type of data at an application level, packet
aggregation can be performed in appropriate response to the
frequently changing condition of a channel and the characteristic
of the data desired to be transmitted.
Inventors: |
Lee; Ju-Han (Suwon-si,
KR), You; Ho-Jeong (Suwon-si, KR), Kim;
In-Hwan (Suwon-si, KR), Chang; Seung-Gi (Seoul,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-si, KR)
|
Family
ID: |
38371703 |
Appl.
No.: |
12/278,097 |
Filed: |
November 6, 2006 |
PCT
Filed: |
November 06, 2006 |
PCT No.: |
PCT/KR2006/004595 |
371(c)(1),(2),(4) Date: |
August 01, 2008 |
PCT
Pub. No.: |
WO2007/094547 |
PCT
Pub. Date: |
August 23, 2007 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20090175190 A1 |
Jul 9, 2009 |
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Foreign Application Priority Data
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|
|
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Feb 16, 2006 [KR] |
|
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10-2006-0015157 |
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Current U.S.
Class: |
370/252 |
Current CPC
Class: |
H04B
3/54 (20130101); H04B 2203/5408 (20130101); H04B
2203/5495 (20130101) |
Current International
Class: |
H04L
12/26 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Ly; Anh-Vu
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
What is claimed is:
1. A method of aggregating packets in a power line communication
(PLC) network comprising: by performing a PLC channel estimation,
determining whether or not a channel condition is good, at a
channel condition determination unit; if the channel condition is
good, determining whether or not data desired to be transmitted is
suitable for packet aggregation according to the type of data, at a
data type determination unit; and if the channel condition is good
and the data desired to be transmitted is suitable for the packet
aggregation, aggregating packets of the data desired to be
transmitted, at a packet aggregation unit, wherein the determining
of whether or not the channel condition is good comprises:
calculating the available bandwidth of the channel by using a
predetermined formula according to whether or not an apparatus
performing the PLC channel estimation uses a channel; and if the
available bandwidth of the channel is equal to or greater than a
reference bandwidth, determining that the channel condition is
good.
2. The method of claim 1, wherein the calculating of the available
bandwidth of the channel comprises calculating the available
bandwidth of the channel by using the following formula if the
apparatus performing the PLC channel estimation communicates by
using the channel:
B.sub.Rev,i.times.P.sub.Success,i.times.(T.sub.Hold,i+T.sub.Rest)
where B.sub.Rev,i,is the modulation bit rate of a packet received
by the apparatus performing the PLC channel estimation during
communication, P.sub.success,i is a ratio that a packet received by
the apparatus performing the PLC channel estimation is decoded
without errors during communication, T.sub.Hold,i is a time ratio
that the apparatus performing the PLC channel estimation occupies
the channel, and T.sub.Rest is a time ratio that no apparatus uses
the channel.
3. The method of claim 1, wherein the calculating of the available
bandwidth of the channel comprises determining a maximum modulation
bit rate as the available bandwidth of the channel when no
apparatus in the PLC network performs communication.
4. The method of claim 1, wherein the calculating of the available
bandwidth of the channel comprises calculating the available
bandwidth of the channel by using the following formula if the
apparatus performing the PLC channel estimation does not use the
channel and other PLC apparatuses use the channel:
.times..times..times..times..times. ##EQU00002## where N is a
number of modulation methods used in the PLC network, T.sub.Rest is
a time ratio that no apparatus uses the channel, B.sub.Rev,j is a
modulation bit rate of a packet modulated using a j-th modulation
method among N modulation methods, T.sub.Success,j is a ratio that
a packet modulated using a j-th modulation method among N
modulation methods is decoded without errors, and T .sub.Hold,j is
a time ratio that a packet modulated using a j-th modulation method
uses the channel wherein N is an integer.
5. A non-transitory computer readable recording medium having
embodied thereon a computer executable program for executing a
method of aggregating packets in a power line communication (PLC)
network, wherein the method comprises: by performing a PLC channel
estimation, determining whether or not a channel condition is good;
if the channel condition is good, determining whether or not data
desired to be transmitted is suitable for packet aggregation
according to the type of data; and if the channel condition is good
and the data desired to be transmitted is suitable for the packet
aggregation, aggregating packets of the data desired to be
transmitted wherein the determining of whether or not the channel
condition is good comprises: calculating the available bandwidth of
the channel by using a predetermined formula according to whether
or not an apparatus performing the PLC channel estimation uses a
channel; and if the available bandwidth of the channel is equal to
or greater than a reference bandwidth, determining that the channel
condition is good.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
This application is a National Stage Entry of PCT/KR2006/004595,
filed on Nov. 6, 2006, which claims the benefit of Korean Patent
Application No. 10-2006-0015157, filed on Feb. 16, 2006, in the
Korean Intellectual Property Office, the disclosures of which are
incorporated herein in their entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power line communication (PLC),
and more particularly, to a packet aggregation method and apparatus
in a PLC network.
2. Description of the Related Art
A power line communication (PLC) network is one of a plurality of
local communication networks. PLC technology uses existing power
lines in houses. Accordingly, unlike Ethernet, a PLC network does
not need additional wiring, and can be used in basements or shaded
areas that wireless technology cannot reach.
Packets transmitted through a network include header information
for transmission control, flow control and link control, in
addition to data desired to be transmitted. This header information
lowers the efficiency of data transmission through a network. To
address this problem, a packet aggregation technique is used.
However, since it is difficult to apply an ordinary packet
aggregation technique used in a wireless local area network (WLAN)
directly to a PLC network, a packet aggregation technique suitable
for a PLC network is needed.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for packet
aggregation that can be applied to a power line communication (PLC)
network.
The present invention also provides a computer readable recording
medium having embodied thereon a computer program for executing the
packet aggregation method.
According to an aspect of the present invention, there is provided
a method of aggregating packets in a power line communication (PLC)
network including: by performing a PLC channel estimation,
determining whether or not a channel condition is good; if the
channel condition is good, determining whether or not the data
desired to be transmitted is suitable for packet aggregation
according to the type of data; and if the channel condition is good
and the data desired to be transmitted is suitable for the packet
aggregation, aggregating packets of the data desired to be
transmitted.
According to another aspect of the present invention, there is
provided an apparatus for packet aggregation in a power line
communication (PLC) network, including: a channel condition
determination unit that determines whether or not a channel
condition is good by performing a PLC channel estimation; a data
type determination unit that, if the channel condition is good,
determines whether or not a data desired to be transmitted is
suitable for packet aggregation according to the type of data; and
a packet aggregation unit that aggregates packets of the data
desired to be transmitted if the channel condition is good and the
data desired to be transmitted is suitable for the packet
aggregation.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
FIG. 1 illustrates an example of applying packet aggregation to
data packets; and
FIG. 2 is a flowchart illustrating a method of aggregating packets
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The present invention will now be described more fully with
reference to the accompanying drawings, in which exemplary
embodiments of the invention are shown.
FIG. 1 illustrates an example of applying packet aggregation to
data packets.
A medium access control (MAC) layer performs an important role in a
network. MAC technology in a power line communication (PLC) network
employs a carrier sense multiple access/collision avoidance
(CSMA/CA) method in the same way as a wireless local area network
(WLAN) does. That is, not only is data transmitted through a
transmission medium, but also header information for transmission
control, flow control, or link control is transmitted. For header
information, a separate frame is used, or a separate field is
assigned in a frame.
Frequent transfers of this header information lower an overall
efficiency of the MAC layer. In order to enhance the data
transmission efficiency of the MAC layer, packet aggregation is
used.
Packet aggregation is performed as follows. Referring to FIG. 1,
data packets having common header information 10 through 1N are
collected in operation 100, and common headers 11 through 1N are
removed in operation 110 leaving the first common header 10. Then,
by sequentially connecting the collected data 20 through 2N to the
common header 10, one data packet is generated in operation
120.
By performing packet aggregation, network resources required for
repeatedly transmitting common header information can be saved.
FIG. 2 is a flowchart illustrating a method of aggregating packets
according to an embodiment of the present invention.
Generally, it is important to determine which packet the packet
aggregation is applied to.
Uniform application of packet aggregation cannot guarantee quality
of service (QoS). Since a required delay or bandwidth varies with
respect to an application, it is inefficient to uniformly apply
packet aggregation. Also, a channel condition changes frequently in
a PLC environment. In the present invention, a packet aggregation
method which selectively applies packet aggregation reflecting the
characteristic of a channel and QoS requirement information of an
application in a PLC network is suggested.
In the packet aggregation method according to the current
embodiment of the present invention, two variables are considered.
One is a channel condition at a physical (PHY) level, and the other
is the characteristic of an application at an application
level.
In order to identify a channel condition at the PHY level, channel
estimation is performed in operation S100. By using the result of
the channel estimation, it is determined whether or not the channel
condition is good in operation S110.
In order to measure the channel condition at the PHY level, an
available bandwidth of a channel is calculated by using a
predetermined formula.
If an apparatus for performing the packet aggregation method
according to the current embodiment of the present invention, that
is, an apparatus performing PLC channel estimation, is using a
channel, the available bandwidth of the channel is calculated by
using the following equation 1:
B.sub.Rcv,i.times.P.sub.Success,i.times.(T.sub.Hold,i+T.sub.Rest)
(1) where B.sub.Rcv,i is the modulation bit rate of a packet
received by the apparatus performing the PLC channel estimation
during communication, P.sub.Success,i is a ratio that a packet
received by the apparatus performing the PLC channel estimation is
decoded without errors during communication, T.sub.Hold,i is a time
ratio that the apparatus performing the PLC channel estimation
occupies the channel, and T.sub.Rest is a time ratio that no
apparatus uses the channel.
When no apparatus in the PLC network communicates, the available
bandwidth of the channel is calculated by using the following
equation 2: B.sub.Max (2) where B.sub.Max is the maximum modulation
bit rate in a system.
When the apparatus performing the PLC channel estimation does not
use the channel and other PLC apparatuses are using the channel for
communication, the available bandwidth of the channel is calculated
by using the following equation 3:
.times..times..times..times..times. ##EQU00001## where N is a
number of modulation methods used in the PLC network, T.sub.Rest is
a time ratio that no apparatus uses the channel, B.sub.Rcv,j is a
modulation bit rate of a packet modulated using a j-th modulation
method among N modulation methods, T.sub.Success,j is a ratio that
a packet modulated using a j-th modulation method among N
modulation methods is decoded without errors, and T.sub.Hold,j is a
time ratio that a packet modulated using a j-th modulation method
uses the channel.
After the available bandwidth of the channel is calculated
according to the equations described above, if the calculated
bandwidth is equal to or greater than a reference bandwidth, it is
determined that the channel condition is good.
If the channel condition is not good, packet aggregation is not
performed and ordinary data transmission is performed in operation
S140.
If the channel condition is good, it is determined whether or not
packet aggregation is applied with respect to the characteristics
of an application at an application level in operation S120.
In an embodiment of the present invention, types of data are
divided into class A type and class B type. Class A type data has a
large packet size for data desired to be transmitted, and a maximum
delay requirement in a network is long. The maximum delay
requirement is a requirement that a maximum delay in a network
should be equal to or less than a predetermined value. In the case
of class A type data, since the maximum delay requirement is long,
a long delay in a network is acceptable. Accordingly, class A type
data is suitable for packet aggregation. Examples of class A type
data include content for high definition televisions (HDTVs), and
MPEG data. If the data desired to be transmitted is class A type
data, packet aggregation is performed in operation S130 and the
data is transmitted in operation S140.
Class B type data has a small packet size for data desired to be
transmitted, and a maximum delay requirement in a network is short.
Accordingly, a long delay in a network is not acceptable for class
B type data. If packet aggregation is applied to Class B type data,
a delay in a network occurs. Accordingly, class B type data is not
suitable for packet aggregation. Examples of class B type data
include data for voice over Internet protocol (VoIP), and contents
for interactive games.
If the data desired to be transmitted is class B type data, packet
aggregation is not performed and ordinary data transmission is
performed in operation S140.
As described above, since the decision to aggregate packets is
determined according to the channel condition at a physical level
and the type of data at an application level, packet aggregation
can be performed in appropriate response to the frequently changing
condition of a channel and the characteristic of the data desired
to be transmitted. Accordingly, by using the packet aggregation
method according to the current embodiment of the present
invention, the transmission efficiency of the channel can be
enhanced and the quality of service (QoS) can be guaranteed
compared to a conventional packet aggregation method in which
packet aggregation is uniformly applied.
The present invention can also be embodied as computer readable
codes on a computer readable recording medium. The computer
readable recording medium is any data storage device that can store
data which can be thereafter read by a computer system. Examples of
the computer readable recording medium include read-only memory
(ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy
disks, and optical data storage devices.
While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the present invention as defined by
the following claims. The preferred embodiments should be
considered in descriptive sense only and not for purposes of
limitation. Therefore, the scope of the invention is defined not by
the detailed description of the invention but by the appended
claims, and all differences within the scope will be construed as
being included in the present invention.
According to the method and apparatus for packet aggregation in a
PLC network of the present invention, since a decision on whether
or not to aggregate packets is determined according to the channel
condition at a physical level and the type of data at an
application level, packet aggregation can be performed in
appropriate response to the frequently changing condition of a
channel and the characteristic of the data desired to be
transmitted. Accordingly, transmission efficiency of the channel
can be enhanced and quality of service (QoS) can be guaranteed
compared to a conventional packet aggregation method in which
packet aggregation is uniformly applied.
* * * * *